drm/edid: move displayid validation to it's own function.

We need to use this for validating modeline additions.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 26 insertions, 18 deletions

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 0b95a7f2db03..fac4efc7dfe2 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -3901,6 +3901,29 @@ static void drm_add_display_info(struct edid *edid,
                 info->color_formats |= DRM_COLOR_FORMAT_YCRCB422;
 }
 
+static int validate_displayid(u8 *displayid, int length, int idx)
+{
+        int i;
+        u8 csum = 0;
+        struct displayid_hdr *base;
+
+        base = (struct displayid_hdr *)&displayid[idx];
+
+        DRM_DEBUG_KMS("base revision 0x%x, length %d, %d %d\n",
+                      base->rev, base->bytes, base->prod_id, base->ext_count);
+
+        if (base->bytes + 5 > length - idx)
+                return -EINVAL;
+        for (i = idx; i <= base->bytes + 5; i++) {
+                csum += displayid[i];
+        }
+        if (csum) {
+                DRM_ERROR("DisplayID checksum invalid, remainder is %d\n", csum);
+                return -EINVAL;
+        }
+        return 0;
+}
+
 /**
  * drm_add_edid_modes - add modes from EDID data, if available
  * @connector: connector we're probing
@@ -4212,30 +4235,15 @@ static int drm_parse_display_id(struct drm_connector *connector,
 {
         /* if this is an EDID extension the first byte will be 0x70 */
         int idx = 0;
-        struct displayid_hdr *base;
         struct displayid_block *block;
-        u8 csum = 0;
-        int i;
         int ret;
 
         if (is_edid_extension)
                 idx = 1;
 
-        base = (struct displayid_hdr *)&displayid[idx];
-
-        DRM_DEBUG_KMS("base revision 0x%x, length %d, %d %d\n",
-                      base->rev, base->bytes, base->prod_id, base->ext_count);
-
-        if (base->bytes + 5 > length - idx)
-                return -EINVAL;
-
-        for (i = idx; i <= base->bytes + 5; i++) {
-                csum += displayid[i];
-        }
-        if (csum) {
-                DRM_ERROR("DisplayID checksum invalid, remainder is %d\n", csum);
-                return -EINVAL;
-        }
+        ret = validate_displayid(displayid, length, idx);
+        if (ret)
+                return ret;
 
         idx += sizeof(struct displayid_hdr);
         while (block = (struct displayid_block *)&displayid[idx],